private void createLayer(object sender, EventArgs e)
{
TreeNode selected = tree.SelectedNode;
if (selected.Tag is ContainerController)
{
// model
ContainerController parent = (ContainerController)selected.Tag;
LayerController node = new LayerController(new Layer());
parent.add(node);
// ui
TreeNode added = selected.Nodes.Add(node.getName());
added.Tag = node;
selected.Expand();
}
}